Wastewater Treatment in a coffee processing industry

[swamis]

Would anyone have experience in cofee processing wastewater treatment. We have a system with primary physico-chemical system and a hybrid biological system. Incoming COD is reduced to 1000 - 1500 ppm in the primary. The secondary biological system comprises of a roughing filter that works really great and gets the COD down to 200 - 400 ppm range. This is followed by a SBR, that has a retention close to 6 days based on current flows. However the removal in the SBR is very dissapointing and the best we can get from here is 150 ppm COD in effluent. Note that the BOD is persistent at about 45 - 60 ppm. We have urea and phosphoric acid addition, including micronutrients. The settling is very poor and we get about 950 ML/ 1000 mL in 30 minutes settling. The target is to get COD to less than 100 ppm and BOD less than 50 ppm. Any experience, suggestions will be most welcome!!

Thanks in advance

Stanjo

 

[bimr]

I do not have personal experience with coffee wastewater, but do not see why it would be much different than any other food wastewater.

I would note that it is difficult to obtain greater than 80% BOD removal in a single stage activated sludge system. To get the BOD less than 50 mg/l, you might have to go to a two stage activated sludge process.

Here is a resource for you:

http://www.venden.de/pdfs/wwater.pdf